In 2011, there were 80,000 cases of invasive meticillin-resistant Staphylococcus aureus (MRSA) infections in the United States, resulting in 11,000 fatalities (Chan et al. Chemical Biology and Drug Design. 2013, 82, 418-428). The emergence of multi-drug-resistant bacteria and the lack of new antibiotics in the drug development pipelines of pharmaceutical companies is a major health concern (Butler et al., Journal of Antibiotics. 2011, 37, 413-425). Since 2000, only four antibiotics with new chemical scaffolds were launched; the (i) oxazolidinone Linezolid (2000), (ii) lipopeptide Daptomycin (2003), (iii) pleuromutilin Retapamulin (2007) and (iv) macrocycle Fidaxomicin (2011) (Wright., Chemistry & Biology. 2012, 19, 3-10). Hence, there is an urgent need to develop new classes of antibacterials, especially those against emerging multi-drug-resistant bacteria (Projan. Drug Discovery Today. 2008, 13, 279-280; Cooper and Shlaes. Nature. 2011, 472, 32).